Corrugated flute & ECT selector
Match your packed box weight and shipping method to E-flute, B-flute, C-flute or double-wall corrugated board and 32–48 ECT ratings.
General packaging engineering guideline. Drop and crush testing before full production is available on request.
Questions
E-flute vs B-flute for custom mailer boxes?
E-flute (~1/16 in) folds crisply and has the flattest outer liner for sharp CMYK and Pantone graphics on small-to-medium mailers. B-flute (~1/8 in) adds extra cushioning for larger or heavier mailer boxes.
What does 32 ECT mean?
Edge Crush Test (ECT) measures how many pounds per linear inch a corrugated wall resists before buckling vertically. 32 ECT is the standard single-wall parcel benchmark.
Still have a question? Ask a packaging specialist.
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Corrugated Flute Thickness & ECT Comparison Chart
| Flute Profile | Nominal Thickness | Flutes per Foot | Primary Packaging Application |
|---|---|---|---|
| F-Flute | ~1/32 in (0.8 mm) | ~125 | Micro-corrugated retail cartons & luxury cosmetic mailers |
| E-Flute | ~1/16 in (1.6 mm) | ~90 | Custom printed DTC mailer boxes, subscription & pizza boxes |
| B-Flute | ~1/8 in (3.0 mm) | ~47 | Heavier mailers, retail counter displays, canned/jarred goods |
| C-Flute | ~5/32 in (4.0 mm) | ~39 | Standard RSC shipping cartons (FEFCO 0201) & master cases |
| EB / BC Double-Wall | ~3/16–9/32 in (4.8–7 mm) | Dual layer | Fragile glass, heavy electronics & palletized freight (48+ ECT) |
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<p style="font-size:12px;color:#555;margin-top:6px;">Free tool by <a href="https://cubitpack.com/tools/corrugated-flute-ect-selector">CubitPack Corrugated flute & ECT selector</a> · <a href="https://cubitpack.com/boxes">Custom Boxes</a></p>Popular custom packaging sized with this tool
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